In this video, Mark Yoder (N.P., Oncology) reviews diarrhea and digestion issues related to cancer treatment, and offers some tips for dealing with this common side effect. When you have watery bowel movements more than 3 times a day, you are experiencing diarrhea. Diarrhea may or may not be accompanied by stomach cramps. If you have diarrhea, your first priority must be preventing dehydration by drinking plenty of water and asking your doctor to prescribe you the appropriate medication for relief. It is critical that ongoing diarrhea be addressed, because it can lead to severe dehydration and, in some cases, organ failure; so, be in close contact with your doctor regarding your symptoms.